Question

If y varies directly with x and y = -78 when x = 6, write the equation that represents this direct variation relationship.

Answer 1

y = - 13x

Explanation:

given y varies directly with x, then the equation relating them is

y = kx ← k is the constant of variation

to find k, substitute y = - 78 , x = 6 into the equation

- 78 = 6k ( divide both sides by 6 )

- 13 = k

y = - 13x ← equation of variation